St. Augustine had an answer to this question in City of God. In his very early writings he seemed to believe in Manicheanism - whereby God is not omnipotent and partakes of good only. His more mature writings, after he read Plato (whom in The Republic seemed to suggest a Manichean answer to the problem of evil himself) led him to think that evil was more the absence of God's good, and that human understanding of evil is always limited. The divine plan of God is without question (for Augustine), and to try and conceive of divine providence is an arrogant and - what's more - prideful sin. This is also connected to Augustine's conception of pride as the Original Sin - in eating the fruit and putting themselves above God, Adam and Eve's original crime was pride.
That said, I remain unconvinced by this. If the divine plan is above human comprehension, then politically inclined despots could (as was done throughout the medieval period) assume authority on Earth through evil means and simply defer to God when asked what justified their having power. And Augustine seems to be ok with this if memory serves. Passive obedience toward the state insofar as it does not prevent one from following God's laws (and it is subject to so much interpretation who is to say what is and isn't if the divine law is unconceivable in human terms) legitimizes unjust authority (to be sure, Augustine thinks we still are ultimately responsible for our actions and all deserve damnation because of the original sin - even babies and unborn). Aquinas is better on this front despite his writing being soporific to the extreme. And then, Hobbes, having seen the effect of the Schools adopting Aquinas' conception of natural law, is horrified at the revolutionary zeal it apparently fostered.
I think a better answer comes from Rousseau. He suggests that humans are not bedeviled by horrible passions in their natural state (at a time before written history and society) but rather, it is the founding of civil society, the division of labor, private property, and reason (and one can see how much he diverges from his Enlightenment Era brethren here) that exacerbates inequalities and creates evil. He implies, I think, that man's advancement is not ordained by God, but that it proceeds at too feverish a pace. Many people think that this means that original man - for Rousseau - is good (no less than Hannah Arendt, in fact) but that seems to be a serious error. Good and evil is unconceivable without language and society, and Rousseau says as much. There is no justice on a desert island.
Of course, no matter what evil confronts you, McDonalds is always here to provide you the good.
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-RealMcDonalds
